@jannem@fosstodon.org avatar

jannem

@jannem@fosstodon.org

Programmer and computational neuroscientist, now HPC support engineer in Okinawa, Japan.

Photography, bouldering, recreational programming and playing the sanshin are things I do.

Sweden, Osaka and Okinawa are places I particularly care about.

This profile is from a federated server and may be incomplete. Browse more on the original instance.

giuseppebilotta, to GraphicsProgramming
@giuseppebilotta@fediscience.org avatar

It's official now: I hate and variable frequency.

This is re: https://fediscience.org/@giuseppebilotta/111818775682992930

It might just be that I'm more proficient analyzing and working around quirks (happens, when you do mostly for more than a decade) than , but there's so many weird things happening on this machine that I don't know where to start from.

jannem,
@jannem@fosstodon.org avatar

@giuseppebilotta
Is hyperthreading enabled? If so, you may be placing the first two threads on the same core, where they're busy interfering with each other.

jannem,
@jannem@fosstodon.org avatar

@giuseppebilotta
As a rule you should disable hyperthreading for any CPU bound workloads, especially parallel ones. It's permanently disabled on all our HPC systems.

With hyperthreading, threads from different kinds of processes can become more efficient. While one thread waits for memory, the other can use the fpu.

But with parallel CPU bound code all threads will always do the same thing at the same time. They'll all try to use the fpu or fetch memory and just get in each other's way.

mrundkvist, (edited ) to random
@mrundkvist@archaeo.social avatar

Gulligt. Tyska politiker brukar ertappas med fejkad doktorstitel. Civilminister Erik Slottner (KD) nöjde sig med att fejka en pol.mag., och äldre- och socialförsäkringsminister Anna Tenje (M) en master i europeisk administration.

https://www.dn.se/sverige/flera-ministrar-kryddade-sitt-cv-vilseledande/

jannem,
@jannem@fosstodon.org avatar

@mrundkvist

En hel del av våra framstående vänsterpolitiker genom tiderna har inte haft någon akademisk bakgrund alls. Och på högersidan skryter man ibland närmast med "livets hårda skola".

Kan en vanlig examen verkligen vara så viktigt, särskilt när ett avslöjande potentiellt kan skada eller avsluta din karriär?

aeva, to random
@aeva@mastodon.gamedev.place avatar

I know this is both controversial and brave of me to say, but I really hate the "two-column paper" format. {lastname}%y.pdf why are you like this.

jannem,
@jannem@fosstodon.org avatar

@aeva @TheZouave
As a tip: paper authors are usually happy (delighted!) to send you a copy of the paper if you ask. If the citation is somewhat recent you'll at least get a good, crisp pdf, not a third generation photocopy.

But yes, papers are all created for print, not the web. Online repos (biomedcentral, arxiv, journal web sites) often do have a separate list of citations, and sometimes (as for biomedcentral ) links directly to the paper.

jannem,
@jannem@fosstodon.org avatar

@aeva @TheZouave
Most research is paywalled, often even to other researchers. I have published papers that I myself don't have access to. It's absolutely ridiculous. That's why Sci-hub is thriving for instance.

So it's absolutely normal and expected to ask people for papers. I absolutely understand that it feels awkward if you're not used to it though.

jannem,
@jannem@fosstodon.org avatar

@aeva @TheZouave
I agree; it is a crappy bandaid.

But it's a crappy bandaid that even researchers have done for decades, because all incentives point toward keeping this crappy system and no incentives point away.

Again, the first thing needed would be a modern replacement for pdf files, one that does things so much better it's worth the pain of switching. The main audience for papers is other researchers and web pages don't work.

futurebird, to random
@futurebird@sauropods.win avatar

Are there therapists who specialize in helping children who are stressed out giving tech support to their parents?

My mom is a mathematician. She can program w/ punch cards. But, she & Dad just don't keep up with tech anymore. Drives me nuts.

Gave my dad an iPhone for Christmas. They HATE it. Probably would hate any phone. Now they say it's recording their conversations.🙄

Dad holds down the buttons on the side when he picks it up. Activates the voice assistant... they think it's a hacker.

jannem,
@jannem@fosstodon.org avatar

@futurebird @kritischelezer
Never mind parents - I'm 55 and I want that for myself.

Cars, appliances and so on have "safe" UIs; you can't really break anything.

Industrial machinery, power tools, servers and so on are dangerous, but also clearly signal that you better know what you're doing.

Smartphones are the worst of both worlds: their UI tells you it's all safe and easy, while really being dangerous and fragile.

mrundkvist, to random
@mrundkvist@archaeo.social avatar

Jag är en dålig svensk 70-talist, för jag saknar helt kunskap om Broder Daniel.

jannem,
@jannem@fosstodon.org avatar

@mrundkvist
Jag har aldrig hört namnet tror jag. Fast jag är 60-talist (med några månader till godo) så jag har en ursäkt.

gsuberland, to random
@gsuberland@chaos.social avatar

valheim is so pretty

jannem,
@jannem@fosstodon.org avatar

@gsuberland
It's by far my current favorite game. I have an embarrassing number of hours in it - and I just started a new world a couple weeks ago.

JoeRess, to random
@JoeRess@fosstodon.org avatar

It's OK to despise everything about the very idea of monarchy, while also having empathy for a man and his family who are facing the reality of a cancer diagnosis.

jannem,
@jannem@fosstodon.org avatar

@JoeRess
Also even if you dislike the man himself. Nobody deserves a cancer diagnosis.

On the other hand, having a serious disease should never shield you from being criticized either.

aeva, to random
@aeva@mastodon.gamedev.place avatar

hm, so there's a topic I'm interested in reading existing research on, but I don't know exactly what to search for.

Specifically, I'm looking for examples of or research about visual programming languages where the for making gui programs, where the language is also the program's own UI. The only example that comes to mind for me right now is the one in Nintendo's Labo games.

jannem,
@jannem@fosstodon.org avatar

@aeva
Smalltalk should fit, as should Racket. Perhaps Godot counts too, as someone mentioned.

AAKL, to vr
@AAKL@noc.social avatar

deleted_by_author

    •
    jannem,
    @jannem@fosstodon.org avatar

    @AAKL @markv @AP
    Trying to own the mindshare, I believe. If you can establish a new term, you're the first, fresh entrant and not another attempt in an already crowded field.

    mrundkvist, to Stockholm
    @mrundkvist@archaeo.social avatar

    from ! plans: vacuum house and play at my buddy's. What are you all up to?

    jannem,
    @jannem@fosstodon.org avatar

    @mrundkvist
    Went to book my stomach endoscopy (regular thing, nothing to worry about). Now having an afternoon coffee before I go to the airport to pick up my wife.

    It was 26° today - approaching summer temperatures. I'm all for a pleasant winter but this year really doesn't feel normal.

    jannem, to random
    @jannem@fosstodon.org avatar

    Got my copy of by @mwichary delivered here on Okinawa without a scratch.

    And it's beautiful! 2½ volumes full of all you wanted to know about keyboards. It's like a slice of the very geekiest pre-social media internet condensed into book form, and I love it.

    Shift happens, three volumes in a slipcase.

    cadey, to random
    @cadey@pony.social avatar

    "No way to prevent this" says users of only programming language where this regularly happens

    jannem,
    @jannem@fosstodon.org avatar

    @cadey Rust is getting accepted as part of the Linux kernel. Should be entirely possible to do it.

    Be the change you want to see!

    aeva, to random
    @aeva@mastodon.gamedev.place avatar

    I'm feeling weirdly conflicted about the prospect of the military potentially avoiding funding C and C++ work due to memory safety reasons. On one hand I'm generally against politicians making decisions about what parts of computer science are compulsory. However if the military were to eventually be banned from using C++, as a pacifist I find the idea weirdly compelling. That certainly would reduce the likelihood of any software I write being misused to murder people at scale.

    jannem,
    @jannem@fosstodon.org avatar

    @aeva @moffintosh
    Maybe that computer science is fully free to continue doing whatever it wants?

    This is all about IT industry projects, really, not people designing toy languages to make a mathematical point.

    I think of the relationship between CS and IT as much the same as physics to engineering. We do regulate engineering for some very good, literally solid reasons.

    gsuberland, to random
    @gsuberland@chaos.social avatar

    made some code use 7x less memory and 7x faster by allocating up to 32 times more things.

    computers are weird.

    jannem,
    @jannem@fosstodon.org avatar

    @gsuberland I believe Python takes 24 bytes per element in a list (AFAIK they're always references).

    Probably overall well motivated from an ergonomics perspective but it kills cache locality. Often worth using numpy arrays even for things that have nothing to do with math.

    saja0486, to random
    @saja0486@mas.to avatar

    Most faved Flickr photo of 2023
    https://flic.kr/p/2oqqX9t

    jannem,
    @jannem@fosstodon.org avatar

    @saja0486
    As a coincidence, my most favourited image was an Okinawan male rock thrush:

    People like birds I guess. Or rock thrushes.

    giuseppebilotta, to random
    @giuseppebilotta@fediscience.org avatar

    One of the reviewers for the manuscript on introducing CPU support in #GPUSPH asked for scalability tests on more than 8 cores (when I originally wrote the whole thing the only decent CPU I had at hand was an AMD Ryzen 7 3700X 8-Core Processor). It's a reasonable request, so I've been running tests on the new server we got at #INGV, that sports a dual AMD EPYC 7713 64-Core Processor. The most interesting so far has been that GPUSPH does seem to scale decently, but the baseline is lower.

    #HPC

    jannem,
    @jannem@fosstodon.org avatar

    @giuseppebilotta
    The epyc is likely to be slower per core. Look up the base and boost clock frequencies for your CPU and for the epyc.

    In our system the epyc CPUs are clocked at 2.0ghz. makes them less than half the speed of my desktop per core. But then, my desktop has 16 cores and the dual-cpu nodes have 2 epycs each for 128 cores do it ends up much faster overall.

    They also have much better bandwidth to memory and network but that's another matter.

    gsuberland, to Electronics
    @gsuberland@chaos.social avatar

    today's fun tip: you can detect the state of two switches or buttons using a single input pin on a microcontroller that supports internal pullups (which is most of them) as long as you don't need to detect both being pressed at once.

    to read the button state, turn the internal pullup off, read the pin, turn the pullup on, and read the pin again. if the value changed, no button is pressed. high both times = top button, low both times = bottom button.

    try it: https://www.falstad.com/circuit/circuitjs.html?ctz=CQAgjCAMB0l3BWcMBMcUHYMGZIA4UA2ATmIxAUgpABZsKBTAWjDACgAncMFEYw7rzAYBVSvDYBnQeBEyUNKlQgAzAIYAbSQzYAlGfxmEaUU4upKo0BGwDu88ywEKlnEE5Av3YAdkJ5TFDQJAHNvX39wkGw8E1d7Dy8mPCovSCl3FM9HLNw48BB1LR0uZKo8zPLI1OC2MLLoyIaY-PTpBqSs4VECou03Bu7Kvh6guD1hwwbjUypzJEsYG3tWXi8fVPN0gFlwQk3U-GzLFGs2AA9wFAhhcjHwLJMfEABLADsAFwYON80AHUkAAcAK4aDTAwFsABGIFyaxInjIUAu4BoARQ9DQ8No2RA2wAwgBVNhAA

    jannem,
    @jannem@fosstodon.org avatar

    @gsuberland
    Interesting! Perhaps a little component- intensive for many pins, but for 1-2 it's very doable.

    If the criteria is one input only at a time, another way is a resistor ladder connected to one analog input, and switches grounding the ladder at each step. With enough care choosing resistors you could have as many inputs as your analog resolution.

    sundogplanets, to random
    @sundogplanets@mastodon.social avatar

    If you can see the moon from where you are right now, give a little wave to the cute JAXA SLIM lander that just got there!

    jannem,
    @jannem@fosstodon.org avatar

    @sundogplanets

    ... probably! The Youtube feed is right now still trying to confirm it did land properly.

    kushal, to linux
    @kushal@toots.dgplug.org avatar

    How to install on servers to secure them 100%?

    Correct answers only.

    jannem,
    @jannem@fosstodon.org avatar

    @kushal
    Wrap the chain around the server, attach the blocks, and throw it into Nybroviken.

    That server is not gonna talk to anyone again.

    ianbetteridge, to random
    @ianbetteridge@writing.exchange avatar

    Why look, I could spent all weekend farting around with Emacs to get it to work as a writing tool...

    https://fedoramagazine.org/emacs-for-writers/

    jannem,
    @jannem@fosstodon.org avatar

    @ianbetteridge
    You're saying the title should have been "Is Emacs Great for Writers?"

    kfury, to random
    @kfury@mstdn.social avatar

    I know I’m going to catch a lot of flack for this, but wouldn’t it be within a company’s rights to put out a SDK with a condition that they get a percentage of revenue generated by software created with it? And also within their rights to require that any software making calls to proprietary APIs on their operating system be compiled by that SDK?

    There are tons of examples of this. Is the whole counter-argument that iOS is a monopoly?

    jannem,
    @jannem@fosstodon.org avatar

    @kfury
    Starts to sound a bit more reasonable if eBay was the only store where you are allowed to buy things.

    Perhaps if eBay allowed other stores to exist they wouldn't get into this kind of trouble.

    jannem,
    @jannem@fosstodon.org avatar

    @kfury
    You buy a house, and now you're only allowed to buy things for the house from the one single shop.

    You can't switch shops without selling your existing house and everything in it; then buy a new, different house.

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